1. Field of the Invention
The present invention relates to a management apparatus, a management system, and a method of controlling the management apparatus, and more particularly to a management apparatus that controls a plurality of image forming apparatuses, a management system including the management apparatus, and a method of controlling the management apparatus.
2. Description of the Related Art
In many offices, a plurality of image forming apparatuses are used at the same time. In such a case, in general, a user identifies an image forming apparatus to be used for printing by a terminal unit that issues an image output command, such as a PC (personal computer).
Further, as for service lives of wear-prone components of an image forming apparatus, the number of rotations of drums and the number of sheets subjected to image formation, for example, are stored in a memory of the apparatus, and when such a number reaches a predetermined value, a warning message notifying a timing for replacing a part associated with the number is displayed on an operation screen. Further, there have been proposed contrivances for reducing maintenance costs concerning replacement of a plurality of wear-prone components (see e.g. Japanese Patent Laid-Open Publication No. 2003-145890 and Japanese Patent Laid-Open Publication No. 2007-33839).
On the other hand, to cope with a case where a plurality of image forming apparatuses are installed, there has been proposed a technique for reducing maintenance work by a system that monitors the frequency of use of each image forming apparatus, and causes an image forming apparatus used less frequently to be selectively operated based on results of the monitoring (see e.g. Japanese Patent Laid-Open Publication No. H07-261610).
Specifically, when the expiration of the service life of each of wear-prone components occurs in each of the image forming apparatuses at infrequent but random intervals, a serviceman has to be frequently called for maintenance work, which is inefficient.
Further, in an environment in which a plurality of image forming apparatuses are installed, when a large number of the same images are to be output at a time by the image forming apparatuses, the quality of the image, such as the hues, sometimes differs between the image forming apparatuses. This causes inconveniences when the user demands the strict identity of each image.
In general, in the image forming apparatus, a high-pressure application member or the like is degraded by a long-term use, and resistance thereof varies. Therefore, the image forming apparatus is designed with an effort to keep the voltage or electric current constant throughout the long-term use, so as to preserve the function of an image forming operation at a level equal to its initial level.
However, in a case where the usage history is not equal between the image forming apparatuses, even when high-pressure settings are provided in the respective apparatuses so as to control the images to be equal between the apparatuses, it is difficult to cause the apparatuses to form images which perfectly match each other, particularly in hues.
For example, in an electrophotographic method, even if a primary transfer device is used for performing constant current control, the device has its voltage value changed from an initial voltage value after a long-term use, so that fine transferability is varied. This causes a change in dot reproduction, which sometimes results in a subtle change in the hues of output images.
Further, the amount of laser beam is adjusted in order to compensate for the degradation of drum characteristics, including lowering of sensitivity caused by a long-term use. It is expected that this results in a change in a fine latent image, causing a change in dot reproduction, which results in a change in the hues and the image properties.
Therefore, it is necessary to cause the respective image forming apparatuses to match in the usage history to the utmost, which means that the usage histories of units provided for respective colors match between the image forming apparatuses.
However, in the aforementioned technique proposed in Japanese Patent Laid-Open Publication No. H07-261610, the frequency of use cannot be adjusted on a color-by-color basis, and hence it is impossible to cope with a case where the image forming apparatuses are capable of performing full-color printing e.g. by a tandem method. This is because the use conditions vary with each device and units associated with each color, due to the use of a monochrome mode. Note that the above-mentioned term “each device” is intended to mean an electrostatic charger, a drum, a cleaner, a developing device, and a transfer device. Further, the above-mentioned term “units” is intended to mean a combination of part or all of the electrostatic charger, the drum, the cleaner, the developing device, and the transfer device.
Further, in Japanese Patent Laid-Open Publication No. H07-261610, a state sometimes occurs in which the image forming apparatuses temporarily cannot output any images since the system is configured such that wear-prone components of all the image forming apparatuses can be replaced at a time.